Manufacturing variations in molded containers, such as glass bottles and jars, are often related to variations in the associated molds of origin. For this reason, it is desirable in an automated manufacturing operation having a plurality of molds to possess the ability of identifying a specific molded container with its mold of origin, and of associating container manufacturing variations with molds of origin for repair or replacement purposes. In an automated plant for manufacturing glass bottles, for example, a machine termed an individual section or IS machine includes a multiplicity of mold cavities and automated apparatus for feeding glass gobs to successive molds to blow the containers. The blown containers are then fed by suitable conveying apparatus to a lehr where annealing takes place, and then to a so-called cold end where inspection and sorting are performed prior to packaging of the containers for shipment. In view of the processing delay between the molding and inspection operations, it is desirable to identify potentially defective mold cavities at an early time in order to reduce scrap. In the same way, it is desirable after a mold cavity has been replaced or repaired closely to inspect containers from that cavity in order to certify proper operation.
U.S. Pat. No. 4,413,738 assigned to the assignee hereof discloses a system for one hundred percent inspection of molded containers for sidewall and finish variations, and for automatically sorting containers from mold cavities that are identified as defective. Each container is routed through one of a plurality of multi-station inspection devices for automated optical inspection of container sidewall and finish. A primary one of the inspection devices includes or has associated therewith an automated cavity inspection device or CID for reading a code molded onto each container and thereby associating containers passing through that inspection device with molds of origin. A finished product computer correlates variations in containers passing through the primary inspection device to defective molds. All containers are then routed through a second CID at which containers originating at the molds identified as defective by the finished product computer are sorted for rejection.
U.S. Pat. No. 4,691,830, also assigned to the assignee hereof, discloses an automated system for inspecting and sorting molded containers as a function of mold cavity of container origin. In a first system section, finished containers are one hundred percent inspected for variations, and a CID is controlled to reject all containers from cavities associated with defective containers. The CID is also coupled to feed sampled containers from selected cavities to an automatic sampling indexer, in which the sampled containers are fed to one or more stations for testing physical container properties, such as rupture pressure, wall thickness and internal volume. The CID and the automatic sampling indexer are connected to a hierarchy of interconnected computers that receive cavity and test information from the various sections and stations of the system, and control the sampling and sorting process based upon predetermined quality standards. A cavity map is maintained that relates cavity code to physical location of the container-forming machine to help identify quality control trends.
Although the inspection and sorting systems disclosed in the noted patents have enjoyed substantial commercial success and economic benefit in operation, further improvements remain desirable. For example, the disclosed systems embody two cavity inspection devices for reading the mold-of-origin codes on the containers, one at the finished product inspection station, and another at the sampling station at which containers from defective molds are sorted and other containers are sampled for quality control testing. It is desirable to eliminate such redundant inspection of container codes, and it is one object of the present invention to provide a method and apparatus for inspecting and sorting containers in which this goal is accomplished. Another and related object of the present invention is to provide a conveyor system and method for selectively removing containers traveling in sequence along a predetermined path for sample inspection or rejection based upon container mold of origin.